Who was creatively responsible for Casablanca?

Casablanca' was directed by Michael Curtiz, produced by Hal B. Wallis and was based on Murray Bennett and Joan Alison's play Everybody Comes To Rick's. Casablanca stars Humphrey Bogart and Ingrid Bergman, as well as featuring Claude Rains, Peter Lorre, and Paul Henraid.

In one way, the film's story editor, Irene Diamond, could be considered largely responsible for the creation of Casablanca. Diamond discovered the unproduced play Everybody Comes To Rick's whilst on a trip to New York in 1941. She convinced producer Hal B. Wallis to buy the play's rights in 1942 for $20k, which was the most anybody in Hollywood had ever paid for an unproduced play. Due to this, Diamond could be regarded as the main creative responsibility for Casablanca, as without her discovery of the play, Casablanca may not have ever been made or even thought of.

In another way, producer Hal B. Wallis could be considered predominantly responsible for Casablanca. Multiple film critics, including notable critic Roger Ebert, have named Wallis the 'key creative force' of Casablanca because of his massive attention to detail of production - down to insisting on using a real parrot for the Blue Parrot bar.

Finally, the last person that I believe can be regarded as widely creatively responsible for Casablanca is director Michael Curtiz. Curtiz knew close to nothing about the plot as he saw it through images, and this is what he wanted his audience to see. Critic Roger Ebert commented that in Casablanca "very few shots... are memorable as shots" as Curtiz wanted images to express the story rather than to stand alone.

Overall, despite there being multiple people creatively responsible for Casablanca, including cinematographer Arthur Edeson who contributed largely to the underlying film noir style of the film and composer Max Steiner who managed to interlace the most important song of the film ('As Time Goes By') into almost every scene, I believe that Casablanca's auteur is Michael Curtiz. Curtiz was notable in Hollywood for introducing a new and unique visual style; this is obvious in Casablanca which helped it stand out amongst most of the films in its era and become a Hollywood classic.